1. Field of the Invention
The present invention relates to scanning radio receivers. More particularly, the present invention relates to a system and method of programming a scanning radio receiver by querying a frequency and linked descriptor database using a geographic search reference.
2. Description of the Related Art
Scanning radio receivers are devices that sequentially tune through plural radio frequencies until a pertinent radio broadcast is detected, at which time the scanning radio receiver stops the scanning process and receives the detected radio broadcast, usually routing the detected audio signals to a loudspeaker or earphone. The detection of a signal causes the scanning radio receiver to open a squelch gate that couples the received signals to the loudspeaker. Once the broadcast ceases, the squelch gate closes and the scanning radio receiver resumes the frequency scanning process. Scanning radio receivers are also called scanning radios, or simply “scanners.” Most scanners are capable of scanning several radio frequency bands. Examples of radio bands accessible with modern scanners are listed in Table 1.
TABLE 1HF Band25-29MHzVHF-Lo Band30-50MHzVHF-Hi Band144-174MHzUHF Band406-512MHz800 MHz Band806-1300MHz
Radio frequency bands are defined by regulatory authorities, such as the Federal Communications Commission (FCC) in the United States. The list of bands above is not exhaustive, and those skilled in the art are familiar with other bands and numerous sub-bands within the listed bands. The nature of radio scanning is a real-time experience, as there are a great variety of radio communications active at any given instant in time, and, it is a matter of personal preference as to which kinds of communications are desirable, and deemed pertinent by any given user. Some popular kinds of communications include police, fire, emergency medical, weather, sports, aircraft, as well as others. The entities that conduct radio communications within these services are commercial, government, and private organizations that utilize radio systems configured for their particular needs, while remaining compliant with regulatory requirements. Several manufacturers make and sell radio systems that operate according to established standards or that are of a proprietary design. In such systems, one or more radio repeaters are typically employed. The repeaters enable fleets of radios to have broad area radio coverage by transmitting to and receiving from the radio repeaters, which receive and re-transmit (“repeat”) signals from the fleets of radios. Scanning radios generally monitor and receive broadcasts from the transmit side of the repeaters in one of two types of systems, “conventional” radio repeater systems and trunked groups of repeaters (“trunking systems”). In both cases the scanner sequentially scans multiple channels, looking for interesting and desirable broadcasts in real time.
Fleet radios commonly employ some form of analog or digital squelch management, which are controlled with squelch “tones.” These tones are detected by the fleet radios, and by scanners, and serve to open and close the receiver's squelch gate. In order to receive a conventional radio broadcast, a scanner must tune to the frequency of transmission, detect the presence of a predetermined squelch tone, and then open the squelch gate. During a scanning operation, plural frequencies are sequentially loaded into the receiver, and then briefly checked for the presence of an expected tone, which indicates the presence of a pertinent broadcast. When a matching broadcast is detected, scanning is ceased, the squelch gate opened, and the broadcast reproduced to the loudspeaker of the radio. Once the broadcast ceases, the lack of the tone causes the squelch gate to closes, and scanning is resumed.
Trunking systems comprise plural repeaters, typically numbering from 2 to 20, which are connected together and are shared by many radio fleets, thereby improving spectrum utilization efficiency. Control signaling is implemented in the trunked radio system radio protocol, which assigns frequencies and talk group codes in real time. These talk group codes direct the radio fleets as to which repeater frequencies to use in real time. In a typical conversation, the frequency of operation changes with every transmission. In order to scan a trunked system, the scanner must be programmed with all the frequencies of the trunked group and must be programmed with one or more talk group codes. One of the trunked repeaters may be assigned as a control channel, which is particularly monitored, looking for predetermined talk group codes that indicated desired broadcasts.
In prior art scanners, the user was responsible for gathering the needed frequencies, squelch tones, and talk group ID codes. These are then meticulously entered into the scanner using the keypad. This approach is tedious and prone to errors, some of which might never be detected, leading to missed reception opportunities. In addition, the user had to be familiar with the concepts of trunked versus conventional scanning, the arrangement and allocation of channels in the memory of the scanner, which is particularly complex in the case of trunked systems because of the storage of both radio frequencies and talk group codes. Additionally, since radio signals have limited range and since radio frequencies are reused over large distances, the user had to find frequencies, tones, and codes utilized in their geographic area before programming the operation of the scanner. Lists of frequencies, tones, and codes are available from a few sources on the Internet. While this simplifies the process of finding frequencies, tones and codes, the process of gathering, selecting, and programming still remains daunting, even to relatively sophisticated users. In prior art scanners, the display was used to indicate the present frequency of reception by displaying a numeric representation of the current frequency, tone or code. This approach was confusing to users because it is difficult to remember what service is using particular frequencies, etc. Some prior art scanners enabled to user to enter alphanumeric phrases that correspond to the service, and operated such that the phrase was displayed during reception. While this is an improvement during operation and reception of the scanner, it made the programming task even more difficult, particularly since most scanners merely had a telephone style numeric keypad. Thus it can be appreciated that there is a need in the art for a significantly simpler system and method of programming frequencies, tones and codes into a radio scanner that adapts to the geographic needs of the user and that provides recognizable indications of what service is being received.